Abstract: Helium leak detection pre-packed box device is an important unit for the TVS-2M fuel rod to change from horizontal to plumb position. The charging device of the pre-packed box consists of a frame, lifting mechanism, jacking mechanism, material shifting mechanism, pushing mechanism, pre-packed box support frame and an electrical control. The frame is made of 8080 aluminum profile, with adjustable accessories such as feet. The lifting mechanism is equipped with a gearbox and drive by a stepping motor, on which an aluminum profile blanking frame is installed. The feeding mechanism adopts double linear motion design, which is divided into linear feeding and plumb bob lifting to avoid the deformation caused by rotation. The pusher mechanism is driven by two unequal cylinders at the same time and the pusher plate is made of polyethylene material. After the development of the equipment, the effect verification was carried out respectively, including the selection of 500 fuel rods for test, the manual inspection of the accuracy of the paddle of the pre-packed device for helium leak detection, and the timing of 330 fuel rods with a stopwatch. The above verification results are in line with or better than the design indicators, which indicates that the design of the device meets the requirements. The conclusion is as followsthe newly developed device can meet the requirements of the TVS-2M fuel rod pre-packed assembly, no scratch or scratch on the surface of the fuel rod after pre-packed assembly, and the accuracy of packing is 100%. It takes 25 minutes to load 330 fuel rods at a time.

Key words: pre-packed box, loading device, fuel rod, double linear motion